Sphingosine 1-Phosphate Receptor 1 and 5 Reciprocally Regulate IL-13 and IL-9 Production in Atopic Dermatitis

Area of Science:

• Immunology
• Dermatology
• Lipidomics

Background:

• Atopic dermatitis (AD) involves T helper (Th) cell skewing, with lipid mediators potentially influencing this process.
• The precise mechanisms linking lipid mediators to Th skewing in AD remain unclear.

Purpose of the Study:

• To identify lipid mediators that regulate cytokine production driving Th skewing in AD.
• To elucidate the role of sphingosine-1-phosphate (S1P) signaling in AD pathogenesis.

Main Methods:

• RNA-sequencing of T cells and non-T cells from AD patients and healthy controls.
• Analysis of differentially expressed genes to identify candidate lipid mediators.
• In vitro cytokine production assays using CD4+ T cells stimulated with lipid mediators and S1P receptors (S1PR1, S1PR5) modulation.

Main Results:

• Differential expression of lipid mediator-related genes, including S1PR5, in AD patient cells.
• Sphingosine-1-phosphate (S1P) increased IL-13 and IL-9 production.
• AD patients showed higher serum S1P levels.
• S1P signaling via S1PR5 suppressed IL-13/IL-9, while S1PR1 enhanced it.

Conclusions:

• S1P signaling contributes to Th2/Th9-driven inflammation in AD.
• Reciprocal regulation of IL-13 and IL-9 production by S1P through S1PR5 and S1PR1 is key in AD pathogenesis.